Work around C++11 nullptr

Provide CXX11_NULLPTR autoconf macro

Author: saper

configure.ac

@@ -42,6 +42,8 @@ AC_TYPE_SIZE_T
 AC_FUNC_MALLOC
 AC_CHECK_FUNCS([floor getcwd strtol])
 
+CXX11_NULLPTR
+
 # Checks for testing.
 AC_ARG_ENABLE(tests, AS_HELP_STRING([--enable-tests], [enable testing the build]),
               [enable_tests="$enableval"], [enable_tests=no])

m4/cxx11_nullptr.m4

@@ -0,0 +1,12 @@
+#serial 1
+AC_DEFUN([CXX11_NULLPTR],
+[
+  AC_REQUIRE([CXX11_STD_AVAILABLE])
+  CXX11_STD_TRY([nullptr], [], [[char *s = nullptr;]],
+  [ $cxx11_cv_prog_cxx_cxx11 ],
+  [
+    AC_DEFINE([HAVE_CXX11_NULLPTR],[1],
+      [Define to 1 C++11 nullptr is available])
+  ],
+  [])
+])

m4/cxx11_std_try.m4

@@ -0,0 +1,54 @@
+#serial 1
+# CXX11_STD_TRY(STANDARD, TEST-PROLOGUE, TEST-BODY, OPTION-LIST,
+#                 ACTION-IF-AVAILABLE, ACTION-IF-UNAVAILABLE)
+# ----------------------------------------------------------------
+# Check whether the C++ compiler accepts features of STANDARD (e.g
+# `cxx98', `cxx11') by trying to compile a program of TEST-PROLOGUE
+# and TEST-BODY.  If this fails, try again with each compiler option
+# in the space-separated OPTION-LIST; if one helps, append it to CXX.
+# If eventually successful, run ACTION-IF-AVAILABLE, else
+# ACTION-IF-UNAVAILABLE.
+AC_DEFUN([_CXX11_STD_TRY],
+[
+AC_LANG_PUSH(C++)dnl
+AC_CACHE_VAL(cxx11_cv_prog_cxx_$1,
+[cxx11_cv_prog_cxx_$1=no
+cxx11_save_CXX=$CXX
+AC_LANG_CONFTEST([AC_LANG_PROGRAM([$2], [$3])])
+for cxx11_arg in $4
+do
+  CXX="$cxx11_save_CXX $cxx11_arg"
+  _AS_ECHO_N([$cxx11_arg ])
+  AC_COMPILE_IFELSE([], [cxx11_cv_prog_cxx_$1=$cxx11_arg])
+  test "x$cxx11_cv_prog_cxx_$1" != "xno" && break
+done
+rm -f conftest.$ac_ext
+CXX=$cxx11_save_CXX
+])# AC_CACHE_VAL
+cxx11_prog_cxx_stdcxx_options=
+case "x$cxx11_cv_prog_cxx_$1" in
+  x)
+    AC_MSG_RESULT([working as-is]) ;;
+  xno)
+    AC_MSG_RESULT([not working]) ;;
+  *)
+    cxx11_prog_cxx_stdcxx_options=" $cxx11_cv_prog_cxx_$1"
+    CXX=$CXX$cxx11_prog_cxx_stdcxx_options
+    AC_MSG_RESULT([working]) ;;
+esac
+AC_LANG_POP(C++)dnl
+])# _CXX11_STD_TRY
+AC_DEFUN([CXX11_STD_TRY], 
+[
+  AC_MSG_CHECKING([for $CXX option to enable ]m4_translit($1, [x], [+])[ feature])
+  _CXX11_STD_TRY($1, $2, $3, ["" m4_expand($4)])
+  AS_IF([test "x$cxx11_cv_prog_cxx_$1" != xno], [$5], [$6])
+])
+AC_DEFUN([CXX11_STD_AVAILABLE],
+[
+  cxx11_save_CXX=$CXX
+  AC_MSG_CHECKING([for $CXX to have C++11 rvalue references])
+  _CXX11_STD_TRY([cxx11], [], [[double&& d = 2]],
+  [[ -std=c++11 -std=c++0x -qlanglvl=extended0x -AA ]])
+  CXX=$cxx11_save_CXX
+])

src/util.cpp

@@ -107,7 +107,13 @@ namespace Sass {
 
           // convert the extracted hex string to code point value
           // ToDo: Maybe we could do this without creating a substring
+#ifndef HAVE_CXX11_NULLPTR
+#define nullptr (char **)0
+#endif
           uint32_t cp = strtol(s.substr (i + 1, len - 1).c_str(), nullptr, 16);
+#ifndef HAVE_CXX11_NULLPTR
+#undef nullptr
+#endif
 
           if (cp == 0) cp = 0xFFFD;
 
@@ -401,7 +407,13 @@ namespace Sass {
 
           // convert the extracted hex string to code point value
           // ToDo: Maybe we could do this without creating a substring
-          uint32_t cp = strtol(s.substr (i + 1, len - 1).c_str(), nullptr, 16);
+#ifndef HAVE_CXX11_NULLPTR
+#define nullptr (char **)0
+#endif
+           uint32_t cp = strtol(s.substr (i + 1, len - 1).c_str(), nullptr, 16);
+#ifndef HAVE_CXX11_NULLPTR
+#undef  nullptr
+#endif
 
           if (s[i + len] == ' ') ++ len;